JPH10118204A - Charged particle beam apparatus and operation method thereof - Google Patents

Abstract

(57) Abstract: Provided is a charged particle beam device in which the loss of a charged particle beam is reduced, and an operation method thereof. An arithmetic unit 131 determines in advance a horizontal irradiation point of a beam and a necessary dose based on information such as the shape of an affected part. It is desirable that the interval between the irradiation points in the horizontal direction is about half or less of the diameter of the beam spread by the scatterer 300.
The power supply 160 of the irradiation position setting electromagnets 220 and 221 is controlled by the controller 132. [Effect] A uniform irradiation field can be formed by reducing the loss of the charged particle beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam apparatus that uses a charged particle beam for treating cancer or diagnosing an affected part.

[0002]

2. Description of the Related Art Conventional charged particle beam devices are
-40479. This prior art is shown in FIG.
7 will be described.

In FIG. 17, a charged particle beam 82 has a z
Proceed in the direction. When a sinusoidal current having a phase difference of 90 ° flows through the x-direction scanning electromagnet 80 and the y-direction scanning electromagnet 81, the charged particle beam is scanned in a circular shape by the magnetic field generated in each electromagnet. When a charged particle beam scanned in a circular shape is applied to the scatterer 83, the diameter of the charged particle beam is increased, so that the dose distribution in the irradiation area is as shown in FIG. In the region over 2r, the irradiation dose becomes uniform,
The irradiation dose decreases and becomes non-uniform as it goes outside of r. Therefore, the non-uniform irradiation area is cut by the collimator, and only the irradiation area having a uniform irradiation dose is irradiated to the affected part.

[0004] Japanese Patent Application Laid-Open No. 7-275381 describes that an irradiation range is formed into an arbitrary shape by controlling an electromagnet according to the shape of an affected part.

[0005]

However, in the prior art, since the non-uniform irradiation area is cut by the collimator, the loss of the charged particle beam is large. Further, in order to obtain a wide irradiation field, the scatterer 83 for increasing the beam diameter must be thickened, which causes a problem that the energy loss of the charged particle beam increases.

An object of the present invention is to provide a charged particle beam apparatus in which the loss of a charged particle beam is reduced and an operation method thereof.

[0007]

A feature of the present invention that achieves the above object is that the scatterer enlarges the diameter of the charged particle beam, the emission switching means switches between emission and stop of the charged particle beam, and the electromagnet switches the charged particle beam. An irradiation position or irradiation range of a beam is set, and a control device controls an electromagnet while the charged particle beam is stopped to change the irradiation position or irradiation range.

According to this feature, while the emission switching means stops the emission of the charged particle beam, the control device changes the irradiation position or the irradiation range to irradiate the charged particle beam with the irradiation object. The charged particle beam is radiated at each irradiation position or irradiation range, and the non-uniformity around the irradiation target is larger than when the charged particle beam expanded by a scatterer to cover the entire irradiation target is enlarged. Irradiating area can be reduced, and the loss of the charged particle beam can be reduced. Further, compared to the case where no scatterer is used, the beam diameter is large, so that the number of times of changing the irradiation position or the irradiation range is small, and the control is simple.

Another feature of the present invention is that the control device changes the irradiation position or the irradiation range based on the diameter of the expanded charged particle beam, and the irradiation of the charged particle beam expanded by the scatterer. Since the dose has a substantially Gaussian distribution in the radial direction with the irradiation position as the center, the charged particle beams overlap to form an irradiation region having a uniform irradiation dose, and the irradiation target can be uniformly irradiated with the charged particle beam.

Another feature of the present invention is that a target dose setting device determines a target dose in an irradiation region to be irradiated, a dose measuring device measures a dose of a charged particle beam in each irradiation region, and switches emission. Means is to switch between emission and stop of the charged particle beam based on the target irradiation amount and the irradiation amount measured by the irradiation amount measuring device.

According to this feature, the emission switching means continues the irradiation until the irradiation amount of the irradiation area reaches the target irradiation amount. Therefore, even if the intensity of the charged particle beam changes with time, the irradiation target is irradiated with the beam. Irradiation with uniform density is possible.

If the emission switching means is a high-frequency applying device for applying a high-frequency electromagnetic field including the frequency of the betatron oscillation of the charged particle beam circling the charged particle accelerator to the charged particle beam, the output switching means may circulate around the charged particle accelerator. When the betatron oscillation of the charged particle beam is in a resonance state, the applied high-frequency electromagnetic field increases the amplitude of the betatron oscillation of the charged particle beam to exceed the stability limit of resonance, and the charged particle beam is transmitted from the charged particle accelerator. Is emitted.
At this time, the charged particle beam is constantly emitted, so that the irradiation target can be irradiated with the charged particle beam at a uniform beam density.

Another feature of the present invention is that the energy changing means changes the energy of the charged particle beam,
The irradiation area of the irradiation target can be changed by changing the energy of the charged particle beam while the irradiation is stopped.

Another feature of the present invention is that the charged particle accelerator has emission switching means for switching between emission and stop of the charged particle beam, and the charged particle beam transport system switches between transport and stop of the charged particle beam. Having a scatterer for expanding the charged particle beam,
An electromagnet for setting the irradiation position or irradiation range of the charged particle beam, and a control device for changing the irradiation position or irradiation range based on the diameter of the enlarged charged particle beam are provided.

According to this feature, if the emission switching means emits the charged particle beam orbiting the charged particle accelerator to the irradiation device and the transport switching device transports the charged particle beam to the irradiation device, the charged particle beam is Irradiation is performed on the irradiation target in the irradiation device. When the emission switching unit stops emitting the charged particle beam from the charged particle accelerator to the irradiation device, or when the transport switching device stops the charged particle beam, irradiation of the irradiation target with the charged particle beam is also stopped.
Since the switching of the irradiation is performed by two switching means, the safety is higher. Further, the emission switching means or the transport switching device stops emitting the beam, and the control device changes the next irradiation position or irradiation range based on the diameter of the charged particle beam enlarged by the scatterer, and is equal at each position. When irradiating the dose, the irradiation dose of the charged particle beam expanded by the scatterer is almost Gaussian in the radial direction with the irradiation position as the center, so the charged particle beam can overlap and create an irradiation area where the irradiation dose is uniform The irradiation target can be uniformly irradiated with the charged particle beam. In addition, since the non-uniform irradiation area around the uniform irradiation area can be reduced, the loss of the charged particle beam can be reduced. Further, compared to the case where no scatterer is used, the beam diameter is large, so that the number of times of changing the irradiation position or the irradiation range is small, and the control is simple.

Another feature of the present invention is that the apparatus further comprises a movement detecting means for detecting a movement of the patient, and the control device controls the emission switching means based on the movement of the patient detected by the movement detection. In addition, the body movement caused by the patient's respiration, cough, and the like is detected, and the charged particle beam is irradiated when the affected part is almost stationary, so that the irradiation target can be accurately irradiated.

[0017] In cancer treatment using a charged particle beam,
It is necessary to change the energy of the charged particle beam to be irradiated depending on the depth of the irradiation target. In this case, the energy of the charged particle beam orbiting the charged particle accelerator is changed in the acceleration stage, or the material on the plate such as graphite is placed where the charged particle beam of the irradiation device passes, and the emitted charged particle beam is Irradiation with varying energy.

A feature of the present invention that achieves the above object is that the scatterer enlarges the diameter of the charged particle beam, the beam emitting means emits the charged particle beam from the charged particle accelerator, and the electromagnet moves to the irradiation position of the charged particle beam or An irradiation range is set, and a control device controls an electromagnet during an injection operation, an acceleration operation, or a deceleration operation of the charged particle accelerator to change an irradiation position or an irradiation range.

According to this feature, after the beam emitting means emits the charged particle beam, the charged particle accelerator operates in the deceleration mode,
Since the control device changes the irradiation position or irradiation range and irradiates the charged particle beam irradiation target while the beam incidence operation or acceleration operation is performed and the beam is not emitted,
The irradiation target is irradiated with the charged particle beam for each irradiation position or irradiation range, and the amount of radiation generated around the irradiation target is smaller than when the charged particle beam expanded by the scatterer to cover the entire irradiation target is enlarged. The uniform irradiation area can be reduced,
The loss of the charged particle beam can be reduced. Further, compared to the case where no scatterer is used, the beam diameter is large, so that the number of times of changing the irradiation position or irradiation range is small, and the control is simple.

A feature of the present invention that achieves the above object is that the scatterer enlarges the diameter of the charged particle beam, the kicker magnet moves the charged particle beam from the orbit to the emission trajectory, and the electromagnet moves to the irradiation position of the charged particle beam. Alternatively, the irradiation range is set, and the control unit changes the irradiation position or irradiation range by controlling the electromagnet during the injection operation, acceleration operation, or deceleration operation of the charged particle accelerator based on the diameter of the enlarged charged particle beam. It is in.

According to this feature, after the kicker magnet moves the charged particle beam from the orbit to the emission orbit and emits the beam, the charged particle accelerator performs the deceleration operation, the beam injection operation, or the acceleration operation to emit the beam. While not
The control device changes the irradiation position or irradiation range based on the diameter of the expanded charged particle beam and irradiates the charged particle beam irradiation target, so that the irradiation target is irradiated with the charged particle beam for each irradiation position or irradiation range. As compared with the case where the charged particle beam expanded by the scatterer so as to cover the entire area of the irradiation target, a non-uniform irradiation area formed around the irradiation target can be reduced, and the loss of the charged particle beam can be reduced. Further, compared to the case where no scatterer is used, the beam diameter is large, so that the number of times of changing the irradiation position or irradiation range is small, and the control is simple. In addition, since the irradiation dose of the charged particle beam expanded by the scatterer is almost Gaussian in the radial direction with the irradiation position as the center, the irradiation region can be created by overlapping the charged particle beams and the irradiation dose is uniform. The target can be uniformly irradiated with the charged particle beam.

The charged particle beam is emitted immediately after the kicker electromagnet is excited, and the time during which the kicker electromagnet is excited is about the time that the beam makes one round of the orbit. It is all emitted at this time. Thereafter, while the charged particle accelerator performs the deceleration operation, the beam injection operation, or the acceleration operation, the irradiation position or the irradiation range is changed.
It is possible to continuously use the beam emitted in a short time to make a circuit.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) A charged particle beam apparatus according to a first embodiment of the present invention will be described with reference to FIG. The charged particle beam apparatus according to the present embodiment includes a pre-stage accelerator 98, a synchrotron type accelerator 1
00, a rotary irradiation device 110 and a control device group 140. Low-energy ions are in the pre-accelerator 9
8, the light is incident on the accelerator 100, accelerated by the accelerator 100, emitted to the rotating irradiation device 110 of the treatment room 101, and the ion beam is used for the treatment.

The main components of the accelerator 100 will be described. The accelerator 100 applies a high-frequency electromagnetic field to the charged particle beam orbiting the accelerator 100 to increase the betatron oscillation of the charged particle beam, to exceed the resonance stability limit, and to bring the betatron oscillation of the charged particle beam into a resonance state. This is an accelerator that emits a charged particle beam from the accelerator.

The accelerator 100 includes a bending electromagnet 146 for bending the orbiting charged particle beam, a high-frequency accelerating cavity 147 for applying energy to the orbiting charged particle beam, and a magnetic field applied to the orbiting charged particle beam to cause the betatron oscillation to resonate. The multi-pole electromagnet 145 and the multi-pole electromagnet 11, and a high frequency applying device 120 for applying high frequency to the orbiting charged particle beam to increase betatron oscillation are provided. Further, current is supplied to the bending electromagnet 146, quadrupole electromagnet 145, and multipole electromagnet 11, and power is supplied to the accelerator power supply device 165 that supplies power to the high-frequency acceleration cavity 147 and to the emission high-frequency application device 120. An emission high frequency power supply 166 is provided.

After being emitted from the accelerator 100, the transport system 17
The beam transported to the treatment room 101 in 1 is a rotary irradiation device 1
At 10 the patient is irradiated.

The rotary irradiation device 110 will be described. The rotary irradiation device 110 includes a quadrupole electromagnet 150 and a bending electromagnet 151 for transporting an output beam emitted from the accelerator 100 to an irradiation target, and a power supply device 170 for supplying a current to the quadrupole electromagnet 150 and the deflection electromagnet 151. .

Further, the rotary irradiation device 110 has an irradiation nozzle 111. The irradiation position of the irradiation nozzle 111 is x
220, 221 for moving in the direction and the y direction
Is provided. Here, the x direction is a direction parallel to the deflection surface of the deflection electromagnet 151, and the y direction is a direction perpendicular to the deflection surface of the deflection electromagnet 151. A power supply device 160 for supplying a current is connected to the electromagnets 220 and 221. Electromagnet 220,
A scatterer 300 for increasing the beam diameter is provided downstream of 221. Further, further downstream of the scatterer 300, a dose monitor 301 for measuring the irradiation dose distribution of the beam.
Is installed. Further, a collimator 225 is installed immediately before the patient to be irradiated so as not to damage normal tissues around the affected part.

FIG. 2B shows a beam intensity distribution 302 enlarged by the scatterer 300. The beam spread by the scatterers has a nearly Gaussian distribution. Therefore, in a state where the beam emission from the accelerator is stopped, as shown in FIG. 2B, when the beam is shifted by about half the diameter of the beam expanded by the scatterer 300 and the same dose is irradiated at each position, the superposition of the beams is performed. As a result, the irradiation dose 303 becomes substantially the same even at a position other than the irradiation center position of the beam. Therefore, it is determined that the irradiation dose determined in advance in the treatment plan has been irradiated.
After confirming in step (1), the beam from the accelerator is stopped, the irradiation position is moved, and the procedure for emitting the beam from the accelerator is repeated, so that the affected part can be uniformly irradiated.

On the other hand, the non-uniform irradiation dose
Is the area outside. However, the non-uniform area is small as compared with a case where the irradiation area 2r having a uniform irradiation dose is realized by scanning the charged particle beam in a circular shape. Therefore, the loss of the charged particle beam can be reduced. Further, since the diameter of the beam spread by the scatterer 300 is smaller than that in the case where the charged particle beam is scanned in a circular shape, the thickness of the scatterer 300 can be reduced. Therefore, the energy loss of the charged particle beam can be reduced.

FIG. 3 shows an example of the relationship between the depth in the body and the irradiation dose of the ion beam. The peak of the irradiation dose in FIG. 3 is called a Bragg peak. The position of the Bragg peak changes depending on the beam energy. Therefore, in the irradiation nozzle 111, as shown in FIG. 4, a range shifter 222 for adjusting the energy and the energy width of the beam, a ridge filter 223, and a patient bolus 224 for changing the energy in accordance with the shape of the affected part in the depth direction are installed. The ridge filter 223 has a structure in which peaks and valleys repeat in the x direction in FIG. Particles passing through this peak have a large decrease in energy, and particles passing through a valley have a small decrease in energy, and have an energy distribution corresponding to the height of the peak and the height of the valley. Can be made. In the present embodiment, a ridge filter is used in which the energy width of the charged particle beam matches the position where the thickness of the affected part is the largest.

The arithmetic unit 131 is a device for obtaining data necessary for the control unit 132 to control the irradiation of the charged particle beam to the affected part.

The control device 132 emits a charged particle beam from the pre-accelerator 98 to the accelerator 100, accelerates the charged particle beam circulating around the accelerator 100, emits a charged particle beam from the accelerator 100 to the rotary irradiation device 110, and performs rotation irradiation. This is a device for controlling the transport of the charged particle beam in the device 110. Rotary irradiation device 11 from accelerator 100
Since the charged particle beam emitted to 0 is irradiated to the irradiation target, controlling the emission from the accelerator 100 controls the irradiation of the charged particle beam to the affected part.

First, the role of the arithmetic unit 131 will be described, and then the method of operating the charged particle beam device by the control unit 132 will be described.

The arithmetic unit 131 receives information on the affected part, such as the shape and depth of the affected part, the required irradiation dose R, and information on the thickness and material of the scatterer 300 from the operator. Arithmetic unit 1
31 is based on the input affected part information and scattered body information,
The beam diameter, the irradiation area, the irradiation point in the horizontal direction of the beam, the magnitude of the current supplied to the electromagnets 220 and 221, the energy of the charged particle beam irradiated to the affected part, the necessary dose, and the like are calculated. It is desirable that the interval between the irradiation points in the horizontal direction be about half or less of the diameter of the beam expanded by the scatterer 300.

The arithmetic unit 131 is shown in FIG. Arithmetic unit 1
The irradiation area forming unit 133 divides the affected part into a plurality of layers Li (i = 1, 2,..., N) in the depth direction based on the input affected part information, as shown in FIG. The energy calculator 134 calculates a beam energy Ei suitable for irradiation according to the depth of each layer.

The irradiation region forming section 133 further includes
Depending on the shape of i, a plurality of irradiation areas Ai, j (i = 1, 2,... N, j = 1, 2,... M) for irradiating the charged particle beam, the center point Pi, j of the irradiation area Ai, j, And its coordinates (xij, y
ij). Since the intensity of the charged particle beam has a spatially Gaussian distribution, the arithmetic unit 131 determines, based on the diameter of the charged particle beam, that the irradiation area Ai, j overlaps with the adjacent irradiation area to obtain a uniform irradiation dose. The center point Pi, j of each irradiation area Ai, j is determined so as to form an area. Each center point Pi, j
Should be separated by about half the beam diameter.

The irradiation dose calculator 135 calculates a target irradiation dose Rij at each center point Pi, j based on the required irradiation dose R.

The electromagnet current calculation 136 calculates the electromagnet 22 to match the center point Pi, j with the center of the charged particle beam.
The currents IXij and IYij supplied to 0,221 are determined.

The arithmetic unit 131 calculates the beam energy Ei in each layer Li, each irradiation area Ai, j, the center point Pi, j,
Coordinates (xij, yij) of center point Pi, j, target irradiation dose Ri
j and the currents IXij and IYij are output to the controller 132.

FIG. 7 shows an operation method of the charged particle beam apparatus according to this embodiment.

(1) The control unit 132 controls the quadrupole electromagnet 15 to transport the charged particle beam emitted from the accelerator 100 to the rotary irradiation device 110 to the affected part to be irradiated.
The power supply device 170 is controlled so as to supply a current to the zero and the bending electromagnet 151.

(2) The controller 132 controls the pre-accelerator 98
Controls the pre-accelerator 98 so that emits a charged particle beam.

(3) The control device 132 supplies current to the bending electromagnet 146 and the quadrupole electromagnet 145 in order to accelerate the orbiting charged particle beam to the energy Ei, and supplies electric power to the high-frequency accelerating cavity 147. To control the accelerator power supply 165 so as to supply the power.

(4) When the orbiting charged particle beam is accelerated to the energy Ei, the control unit 132 sets the quadrupole electromagnet 145 and the multipole electromagnet in order to bring the betatron oscillation of the orbiting charged particle beam into a resonance state. The accelerator power supply 165 is controlled so as to supply a current to the power supply 11.

Quadrupole electromagnet 145 and multipole electromagnet 11
Is supplied with a current, a resonance stability limit for emission is generated, and the orbiting charged particle beam that has moved outside the stability limit has a betatron oscillation in a resonance state.

(5) The controller 132 controls the electromagnet 22 to match the center of the charged particle beam with the center point Pi, j.
The power supply unit 160 is controlled so as to supply the currents IXij and IYij to 0,221.

(6) The controller 132 sets the target irradiation dose R
ij and the irradiation dose at the center point Pi, j measured by the dose monitor 301 are compared.

(7) If the irradiation dose at the center point Pi, j has not reached the target irradiation dose Rij, the control unit 132 applies the high-frequency emission beam to the rotation irradiation unit 110 to start the emission from the accelerator 100. The output high-frequency power supply 166 is controlled so as to supply power to the device 120.

When power is supplied to the output high frequency applying device 120, a high frequency electromagnetic field is applied to the circulating charged particle beam, and the betatron oscillation amplitude of the circulating charged particle beam increases. When the betatron oscillation amplitude increases and exceeds the stability limit of the resonance of the betatron oscillation, the charged particle beam is emitted from the accelerator 100 to the rotary irradiation device 110. In the rotary irradiation device 110, the charged particle beam is irradiated to the irradiation area Ai, j.

(8) The controller 132 sets the target irradiation dose R
ij and the irradiation dose at the center point Pi, j measured by the dose monitor 301 are compared. If the irradiation dose at the center point Pi, j has not reached the target irradiation dose Rij, the emission continues.

(9) The controller 132 controls the high-frequency power source for emission 166 so as to stop the emission when the irradiation dose at the center point Pi, j has reached the target irradiation dose Rij. Then, the power supply unit 160 is controlled so that the center of the charged particle beam is aligned with the center point Pi, j + 1 of the next irradiation area Ai, j + 1.

(10) When the beam circling the accelerator 100 can be used when the irradiation of the irradiation area Ai, j is shifted from the irradiation of the irradiation area Ai, j + 1, the operation from (5) is performed. If the beam amount and the emission time are insufficient, the operation from (2) is performed to replenish the charged particle beam.

(11) All irradiation areas Ai, j of layer Li
When the irradiation dose reaches the target value, the operation from (1) is performed for the next layer Li + 1, and the entire irradiation area Ai + 1, j is irradiated similarly to the case of the layer Li.

When all layers Li of the affected area have been irradiated, the operation of the charged particle beam device is terminated.

According to the embodiment, the layer LI of the affected area can be irradiated with a uniform irradiation dose. Since the non-uniform irradiation area formed outside the boundary of the affected part layer LI is cut off by the collimator 225, it is possible to irradiate the charged particle beam according to the shape of the affected part. Further, since the area to be cut is smaller than that in the conventional case where the charged particle beam is scanned in a circular shape, the therapeutic irradiation can be performed with a small beam loss. Although the irradiation position of the charged particle beam is set by two electromagnets, the structure is such that the patient bed 112 can be moved.
May be set to control the irradiation position.

If the scatterer 300 is not used, since the diameter of the charged particle beam to be irradiated is small, it is necessary to make the distance between irradiation positions extremely small in order to obtain a uniform irradiation intensity distribution. Control becomes extremely complicated. In the present embodiment, by using the scatterer 300, the charged particle beam has a roughly Gaussian distribution and the beam diameter can be increased to an appropriate size. Distribution can be realized.

As described above, the charged particle beam apparatus of the present embodiment can form a uniform irradiation field by reducing the loss of the charged particle beam.

According to the present embodiment, even when the irradiation target has a complicated shape, the affected part can be irradiated with high accuracy. Further, since the irradiation is continued until the irradiation dose reaches the target, even when the beam intensity changes over time, the affected part can be uniformly irradiated with the beam density.

In this embodiment, a synchrotron is used for the accelerator, but a cyclotron 172 can be used for the accelerator as shown in FIG. Cyclotron 17
Emission and stop of the beam from 2 are performed by controlling the deflector power supply 174 for the deflector 175 by a signal from the control device 132 and supplying and stopping the charged particle beam from the ion source 173.

(Embodiment 2) Next, a second embodiment of the present invention will be described. The device configuration of this embodiment is the same as that of the first embodiment. However, in the present embodiment, the irradiation area of each layer Li of the affected part is not divided in the x direction, but is divided only in the y direction as shown in FIG. That is, the irradiation area Ai, j is wide in the x direction. When irradiating the irradiation area Ai, j, the electromagnet 22
The intensity of the magnetic field generated by 0 is changed, and the charged particle beam is scanned in the x direction and irradiated.

The arithmetic unit 131 controls each irradiation area Ai, j based on the diameter of the charged particle beam so that the irradiation area Ai, j and the adjacent irradiation area overlap each other to form a uniform irradiation dose area.
A center point Pi, j of i, j is determined. Each center point Pi, j is set to be separated by about half of the beam diameter.

Then, the arithmetic unit 131 calculates each irradiation area A
Based on the spread of i, j in the x direction, a magnitude ΔIXij that changes the magnetic field strength of the electromagnet 220 is obtained. Then, similarly to the case of the first embodiment, the beam energy Ei in each layer Li, each irradiation area Ai, j and its center point Pi, j (xij,
yij), target irradiation dose Rij, currents IXij and IYij are obtained, and these and ΔIXij are output to the controller 132.

FIG. 10 shows an operation method of the charged particle beam apparatus according to the present embodiment. Except for (7), it is the same as the first embodiment.

In (7), the control unit 132 controls the accelerator 10
In order to start the emission to the rotary irradiation device 110 from 0, the emission high-frequency power supply 166 is controlled so as to supply power to the emission high-frequency application device 120, and the charged particle beam is scanned and irradiated in the x direction. For this purpose, the power supply 160 is controlled so that the current IXij of the electromagnet 220 changes in the range of ΔIXij.

In this embodiment, when irradiating the irradiation area Ai, j, the intensity of the magnetic field generated by the electromagnet 220 is changed to scan and irradiate the charged particle beam in the x direction. May be changed so that the charged particle beam is scanned and irradiated in the y direction.

According to this embodiment, the same effects as those of the first embodiment can be obtained, and the switching between the emission and the stop of the charged particle beam is performed only in the y direction (or the x direction). The irradiation time can be shorter than in the embodiment.

(Embodiment 3) Next, a third embodiment of the present invention will be described. In this embodiment, a charged particle beam device having the same configuration as that of FIG. 1 is used, but the configuration of the irradiation nozzle 111 and the control device 132 thereof are different. FIG. 11 shows the irradiation nozzle 111 of this embodiment.

In this embodiment, the scatterer 300 is made thinner than in the first embodiment. Since the diameter of the charged particle beam expanded by the scatterer 300 is smaller than that in the first embodiment, the number of irradiation areas Ai, j increases. On the other hand, since the spread of the beam diameter is small, the patient collimator used in the first embodiment is not used. Similarly, since the beam diameter is smaller than that in the first embodiment, the ridge filter and the bolus used in the first embodiment are not used.

In the first embodiment, the energy of the charged particle beam is set to Ei in the accelerator 100. However, in the present embodiment, the controller 132 stops the beam emission from the accelerator 100 and stops the thickness of the range shifter 222. By changing the energy of the charged particle beam,
i.

FIG. 12 shows an operation method of the charged particle beam apparatus according to the present embodiment. Except for (3) and (4), it is the same as the first embodiment.

(3) The controller 132 controls the bending electromagnet 14 to accelerate the charged particle beam circulating to the rated energy E larger than the beam energy Ei of each layer.
The accelerator power supply 165 is controlled so as to supply current to the 6, 4-pole electromagnet 145 and to supply power to the high-frequency acceleration cavity 147. And, to reduce the rated energy E to the energy Ei,
The thickness of the range shifter 222 is adjusted.

(4) When the orbiting charged particle beam is accelerated to the energy E, the control unit 132 sets the quadrupole electromagnet 145 and the multipole electromagnet in order to bring the betatron oscillation of the orbiting charged particle beam into a resonance state. The accelerator power supply 165 is controlled so as to supply a current to the power supply 11.

As described above, the charged particle beam apparatus of this embodiment can form a uniform irradiation field by reducing the loss of the charged particle beam. In addition, the affected part can be accurately irradiated without using a collimator or a bolus for each patient.

In the present embodiment, the electromagnet 2 for setting the irradiation position is set in a state where the thickness of the range shifter is constant and the irradiation depth is constant.
The same procedure is repeated by irradiating a layer having a certain depth and then changing the thickness of the range shifter. The same procedure is repeated, but a virtual layer is formed parallel to the traveling direction of the charged particle beam. After the layers are divided and the irradiation of the electromagnets 220 and 221 is completed with the strength of the electromagnets 220 and 221 kept constant, the irradiation is stopped, and then the thickness of the range shifter is changed, the irradiation of a certain layer is completed. The same irradiation treatment can be performed by changing the intensity.

(Embodiment 4) Next, a fourth embodiment of the present invention will be described. FIG. 13 shows the device configuration of this embodiment. The equipment configuration is different from that of the first embodiment in that a motion detector 250 for detecting the motion of the patient's body is provided and a beam transport system 171 for transporting the charged particle beam to the irradiation device is provided with a charged particle beam. Electromagnet 1 to switch between transport and stop
The other configuration is the same as that of the first embodiment by providing the power supply 77 and the power supply 176. However, power supply 17
No. 6 keeps the beam from irradiating the patient when there is a failure and no current flows, and only when the current is normally applied.

The motion detector 250 may be a distortion detecting device installed on the body surface, or may be a device that detects a patient's motion by a camera. Based on the signal from the motion detector 250, the movement of the patient's body is detected, and only when the body movement is small, a signal for irradiating the patient with a beam is output from the high-frequency power source for emission 166 and the switching electromagnet 177 for switching the beam transport system. Send to 176. Only when the signal indicates that beam irradiation is possible, a high frequency is applied to the charged particle beam from the high-frequency power source for emission 166, and further, a current is applied from the power source 176 to the switching electromagnet 177 of the beam transport system, so that the charged particle beam is rotated by the rotating irradiation device 110. To be supplied to The driving method at this time is shown in FIG. The operation method is the same as that of the first embodiment except for (7) and (9).

In (7), when the irradiation dose at the center point Pi, j does not reach the target irradiation dose Rij and the signal from the motion detector 250 determines that the patient is stationary, the control is performed. The device 132 is provided by the rotation irradiation device 110 from the accelerator 100.
In order to start the emission at the
The high-frequency power source for emission 166 is controlled so as to supply power to the power supply, and at the same time, a current is applied from the power source 176 to the switching electromagnet 177 of the charged particle beam transport system. However, when it is determined from the signal from the motion detector 250 that the patient is not stationary, the power supply of the high-frequency power source for emission 166 and the switching electromagnet 177 of the charged particle beam transport system is controlled to control the charged particle beam. The supply to the rotating irradiation device 110 is stopped.

In (9), the control device 132 sets the center point P
If the irradiation dose of i, j has reached the target irradiation dose Rij, the high-frequency power source for emission 166 is controlled so as to stop the emission, and the current of the switching electromagnet 177 of the beam transport system is stopped, and the charged particle beam is stopped. Supply to the rotary irradiation device 110 is stopped. Then, the power supply unit 160 is controlled so that the center of the charged particle beam is aligned with the center point Pi, j + 1 of the next irradiation area Ai, j + 1.

According to this embodiment, the same effects as those of the first embodiment can be obtained, and the irradiation is switched by two switching means, so that the safety is higher. In addition, since the charged particle beam is irradiated when the affected part is almost stationary, the irradiation target can be irradiated with high accuracy.

(Embodiment 5) Next, a fifth embodiment of the present invention will be described. FIG. 15 shows the device configuration of this embodiment. The configuration of the apparatus differs from that of the first embodiment in that a kicker electromagnet 121 is used to emit a beam from the accelerator. The segmentation of the affected area is performed as shown in FIG.

The kicker magnet 121 is pulse-excited from the power supply 167 of the kicker magnet. When a pulse current is supplied from the power supply 167 to the kicker electromagnet 121 according to a signal from the control device 132, the kicker electromagnet 121 is excited for a time that the beam makes one round of the orbit, and gives a magnetic field to the orbiting charged particle beam. . The orbiting charged particle beam is separated from the orbit and emitted to the transport system 171 as soon as a magnetic field is applied from the kicker magnet 121.
Since a magnetic field is applied to the beam for a period of time that the beam makes one round of the orbit, all charged particles orbiting the accelerator are emitted in this time. Therefore, the kicker magnet 121 is set to 1
After the first pulse excitation, the beam emission ends. This embodiment is suitable for a case where a beam emitted in a short time, such as one round of the orbit, is continuously used.

FIG. 16 shows an operation method in this embodiment.
In (1), after the excitation amount of the electromagnet of the rotary irradiation device 110 is set so that the charged particle beam having the energy Ei can be transported by the signal from the control device 132, the pre-accelerator 98 is set in (2) to (5). From the laser beam to the accelerator 100, acceleration of the circulating charged particle beam, and emission by exciting the kicker electromagnet 121. If it is determined in (6) that the predetermined dose has not been reached for each of the partial areas Ai, j, the incidence, acceleration, and emission of the beam are repeated. Then, after irradiating a predetermined dose to the partial area Ai, j in (6), the beam irradiation position setting electromagnets 220 and 2 are used in (4) by a signal from the control device 132.
The irradiation position is changed by changing the currents IXij and IYij of FIG. If it is determined in (7) that the irradiation of the layer Li has been completed, the irradiation, acceleration, and emission of the beam are repeated until the irradiation layer is changed and all the layers are completed in (8).

[0084]

According to the present invention, the irradiation target is irradiated with the charged particle beam for each irradiation position or irradiation range. Therefore, the charged particle beam expanded by the scatterer to cover the entire irradiation target is enlarged. As compared with the case where the irradiation is performed, a non-uniform irradiation area formed around the irradiation target can be reduced, and the loss of the charged particle beam can be reduced. Further, compared to the case where no scatterer is used, the beam diameter is large, so that the number of times of changing the irradiation position or the irradiation range is small, and the control is simple.

Since the irradiation dose of the charged particle beam expanded by the scatterer has a substantially Gaussian distribution in the radial direction centering on the irradiation position, the charged particle beams may overlap to form an irradiation region having a uniform irradiation dose. The irradiation target can be uniformly irradiated with the charged particle beam.

Further, since the emission switching means continues the irradiation until the irradiation amount of the irradiation area reaches the target irradiation amount, even if the intensity of the charged particle beam changes with time, the beam density can be uniformly applied to the irradiation target. Can be irradiated.

When the emission switching means applies a high-frequency electromagnetic field to the charged particle beam, the amplitude of the betatron oscillation of the charged particle beam increases to exceed the stability limit of resonance, and the charged particle beam is emitted from the charged particle accelerator. Therefore, the charged particle beam is emitted constantly, and the irradiation target can be irradiated with the charged particle beam at a uniform beam density.

Further, since the switching of the irradiation is performed by the two switching means of the emission switching means and the transport switching device, the safety is higher.

Further, since the movement of the body caused by the patient's breathing, coughing, etc. can be detected and the charged particle beam can be irradiated when the affected part is almost stationary, the irradiation target can be irradiated with high accuracy.

Also, as soon as the kicker electromagnet is excited, the charged particle beam is emitted, and all the charged particles orbiting the accelerator are emitted in the time that the beam makes one round of the orbit, and then the irradiation position or Since the irradiation range is changed, it is possible to continuously use a beam emitted in a short time such that the beam makes one round of the orbit.

[Brief description of the drawings]

FIG. 1 is a diagram showing a charged particle beam apparatus according to a first embodiment.

FIG. 2 is a diagram showing a beam intensity distribution 302 enlarged by a scatterer.

FIG. 3 is a diagram showing an example of a relationship between a depth in a body and an irradiation dose of an ion beam.

FIG. 4 is a diagram showing an irradiation nozzle 111 according to the first embodiment.

FIG. 5 is a diagram showing an arithmetic unit 131.

FIG. 6 is a view showing division of an affected part according to the first embodiment.

FIG. 7 is a flowchart showing a procedure of operation of the first embodiment.

FIG. 8 is a diagram showing a charged particle beam device using a cyclotron 172.

FIG. 9 is a diagram showing the division of the affected area according to the second embodiment.

FIG. 10 is a flowchart illustrating a procedure of an operation according to the second embodiment.

FIG. 11 is a diagram showing an irradiation nozzle 111 according to a third embodiment.

FIG. 12 is a view showing a flowchart illustrating the operation procedure of the third embodiment.

FIG. 13 is a view showing a charged particle beam apparatus according to a fourth embodiment.

FIG. 14 is a diagram illustrating an operation method of the charged particle beam device according to the fourth embodiment.

FIG. 15 is a view showing a charged particle beam apparatus according to a fifth embodiment.

FIG. 16 is a flowchart showing a procedure of operation according to the fifth embodiment.

FIG. 17 is a schematic configuration diagram of a conventional charged particle beam device.

[Explanation of symbols]

11 ... multi-pole electromagnet, 80 ... x-direction scanning electromagnet, 81 ... y
Direction scanning electromagnet, 82 ... charged particle beam, 83, 300
… Scatterer, 98… pre-accelerator, 100… accelerator, 101
... treatment room, 110 ... rotating irradiation device, 111 ... irradiation nozzle, 112 ... patient bed, 120 ... emission high frequency application device, 121 ... kicker electromagnet, 131 ... arithmetic device, 13
2 ... control device, 145, 150 ... 4-pole electromagnet, 146
151 ... bending magnet, 147 ... high frequency accelerating cavity, 16
0, 170: power supply unit, 165: power supply unit for accelerator, 1
67, 176: power supply, 166: high frequency power supply for emission, 17
1: beam transport system, 172: cyclotron, 173 ...
Ion source, 174: Deflector power supply, 175: Deflector, 17
8: switching electromagnet, 220, 221: electromagnet, 222
... Range shifter, 223, Ridge filter, 224, Patient bolus, 225, Collimator, 250, Motion detector, 301, Dose monitor, 302, Expanded beam intensity distribution, 303, Irradiation dose.

Claims (18)

[Claims] 1. A charged particle beam apparatus comprising a charged particle accelerator, and irradiating an irradiation target with a charged particle beam supplied by the charged particle accelerator, comprising: a scatterer for expanding a diameter of the charged particle beam; An emission switching means for switching between emission and stop of the laser beam; an electromagnet for setting an irradiation position of the charged particle beam; and a control device for controlling the electromagnet while the charged particle beam is stopped to change the irradiation position. A charged particle beam device characterized by the above-mentioned. 2. The charged particle beam apparatus according to claim 2, wherein the control unit changes the irradiation position based on an enlarged diameter of the charged particle beam. 3. A charged particle beam apparatus comprising a charged particle accelerator, and irradiating an irradiation target with a charged particle beam supplied by the charged particle accelerator, wherein: a scatterer for expanding a diameter of the charged particle beam; An emission switching means for switching between emission and stop of the light, an electromagnet for setting an irradiation position of the charged particle beam, and a magnetic field strength of the electromagnet during emission of the charged particle beam;
Alternatively, a charged particle beam characterized by comprising a control device that changes the magnetic field strength of the electromagnet to a substantially constant range and changes the magnetic field strength and the change range of the magnetic field strength while stopping the emission of the charged particle beam. apparatus. 4. The charged particle beam apparatus according to claim 3, wherein the control device changes the magnetic field strength or the change range based on the diameter of the expanded charged particle beam. 5. An emission switching means, comprising: target dose setting means for determining a target dose in an irradiation area on the irradiation target; and beam quantity measuring means for measuring a dose of a charged particle beam in the irradiation area. 2. The charged particle beam apparatus according to claim 1, wherein switching between the emission and the stop of the charged particle beam is performed based on a comparison between the target irradiation amount and the irradiation amount measured by the irradiation amount measuring unit. 6. The apparatus according to claim 1, wherein said emission switching means is a high-frequency application device for applying a high-frequency electromagnetic field including a frequency of betatron oscillation to said charged particle beam.
Charged particle beam equipment. 7. The charged particle beam apparatus according to claim 1, further comprising energy changing means for changing the energy of the charged particle beam. 8. The charged particle beam apparatus according to claim 5, wherein said energy changing means is provided between said charged particle accelerator and said irradiation target. 9. A charged particle beam apparatus comprising: a charged particle accelerator; and an irradiation device for irradiating an irradiation target with a charged particle beam supplied from the charged particle accelerator, wherein the charged particle accelerator emits the charged particle beam. And an emission switching device that switches between a stop and a stop. The irradiation device includes a scatterer that enlarges the diameter of the charged particle beam, and the charged particle beam in one of a plurality of irradiation regions set in the irradiation target. An electromagnet for setting an irradiation position or an irradiation range of the charged particle beam to irradiate the charged particle beam; and controlling the electromagnet while the charged particle beam is stopped to irradiate a different irradiation area with the charged particle beam. Or a control device for changing the irradiation range,
The said control apparatus changes the said irradiation position or irradiation range based on the diameter of the said expanded charged particle beam, The charged particle beam apparatus characterized by the above-mentioned. 10. A charged particle accelerator, an irradiation device for irradiating the irradiation target with a charged particle beam supplied from the charged particle accelerator, and a charged particle transporting the charged particle beam emitted from the charged particle accelerator to the irradiation device. In a charged particle beam device including a particle beam transport system, the charged particle accelerator has an emission switching unit that switches between emission and stop of the charged particle beam, and the charged particle beam transport system switches between transport and stop of the beam. Having a transport switching device, the irradiating device, for irradiating the charged particle beam to one of a plurality of irradiation regions set to the irradiation object and a scatterer for expanding the diameter of the charged particle beam An electromagnet that sets an irradiation position or an irradiation range of the charged particle beam, and based on a diameter of the expanded charged particle beam, A charged particle beam apparatus comprising: a control unit that changes the irradiation position or the irradiation range to a different irradiation area while the charged particle beam is stopped in order to irradiate the charged particle beam with a different irradiation area. 11. The apparatus according to claim 1, further comprising a motion detecting means for detecting a motion of the patient, wherein the control device controls the emission switching means based on the motion of the patient detected by the motion detection. The charged particle beam device according to claim 1 or 5, wherein 12. A method of operating a charged particle beam apparatus for irradiating a charged particle beam supplied from a charged particle accelerator to an irradiation target, comprising: expanding a diameter of the charged particle beam; and outputting and stopping the charged particle beam. And a step of changing the irradiation position or irradiation range while the charged particle beam is stopped. 13. The method for operating a charged particle beam apparatus according to claim 12, further comprising the step of setting the irradiation position or the irradiation range based on an enlarged diameter of the charged particle beam. 14. The charged particle beam according to claim 12, wherein the step of switching between the emission and the stop of the charged particle beam includes a step of applying a high-frequency electromagnetic field including a frequency of betatron oscillation to the charged particle beam. How to operate the device. 15. A charged particle beam apparatus comprising a charged particle accelerator, and irradiating an irradiation target with a charged particle beam supplied by the charged particle accelerator, wherein: a scatterer for expanding a diameter of the charged particle beam; A beam emitting unit that sets an irradiation position or an irradiation range of the charged particle beam; and controls the electromagnet during the incident operation, the acceleration operation, or the deceleration operation of the charged particle accelerator to control the irradiation position or the irradiation position. A charged particle beam device comprising: a control device that changes an irradiation range. 16. The charged particle beam apparatus according to claim 15, wherein said control device changes said irradiation position based on the diameter of the expanded charged particle beam. 17. A charged particle beam apparatus comprising: a charged particle accelerator; and an irradiation device for irradiating an irradiation target with a charged particle beam supplied from the charged particle accelerator, wherein the charged particle accelerator circulates the charged particle beam. The irradiation device has a kicker electromagnet that moves from an orbit to an emission orbit, the irradiation device includes a scatterer that enlarges the diameter of the charged particle beam, and the charged object is charged into one of a plurality of irradiation regions set in the irradiation target. An electromagnet for setting the irradiation position or irradiation range of the charged particle beam to irradiate the particle beam, and during the injection operation, acceleration operation, or deceleration operation of the charged particle accelerator to irradiate a different irradiation area with the charged particle beam A control device that controls the electromagnet to change the irradiation position or the irradiation range, and the control device includes the expanded charged particle beam. A charged particle beam apparatus characterized by changing the irradiation position or an irradiation range on the basis of the diameter of the beam. 18. A method of operating a charged particle beam apparatus for irradiating a charged particle beam supplied from a charged particle accelerator to an irradiation target, comprising: expanding a diameter of the charged particle beam; Changing the irradiation position or the irradiation range during the acceleration operation or the deceleration operation.